Three-phase transformer construction



May 20, 1958 R. BlSTANY THREE-PHASE TRANSFORMER CONSTRUCTION 3 Sheets-Sheet 1 Filed May 6, 1957 M19 A'ttarwy.

R. BISTANY THREE-PHASE TRANSFORMER CONSTRUCTION 5 Sheets-Sheet 2 W /4 ti 01 /229- May 20, 1958 Filed May 6, 1957 y 20, 1958 R. BISTANY 2,835,875

THREE-PHASE TRANSFORMER CONSTRUCTION Filed May 6, 1957 s Sheets-Sheet :s

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Pay/fiance 8/5 tang by f//s flttornqy- United htates Patent 8 THREE-PHASE TRANSFQRMER CONSTRUCTION Raymond Bistany, Des Piaines, Iil., assignor to General Electric Company, a corporation of New York Application May 6, 1957, Serial No. 657,283

4 Claims. (Cl. 336-) This invention relates to dry-type transformers and more particularly to a unitary three-phase, dry type transformer construction.

Three-phase alternating current power distribution systerns are generally employed in industrial and other high power-utilizing installations, and dry-type transformers (as distinguished from transformers of the oil-filled type) are frequently used in indoor locations to reduce the high distribution voltage to lower utilization voltages. In the conventional delta-Y, or delta-delta three-phase systems, a group of three separate single-phase, dry-type distribution transformers have commonly been used to provide the necessary voltage reduction; this has, however, involved considerable installation expense for the user since a sizeable number of electrical connections are involved in connecting the three individual transformers to the distribution and utilization lines respectively and further, the three transformers have had to be separately mounted and collectively occupied considerable space. Three-phase dry-type transformers have also been constructed in which the three groups of phase windings were arranged on a common core in the manner of the core and coil assemblies of larger oil-filled three-phase transformers; this arrangement has, however, proved to be excessively noisy in many indoor installations which do not have a high ambient noise level.

It is therefore desirable to provide a unitary threephase, dry-type transformer construction which will combine the ease of installation and minimum space of prior three-phase dry-type transformers employing a common core, and the inherent quieter operation of three separate single-phase transformers. Such a transformer must further be simple and readily assembled by the manufacturer, permit pre-connection by the manufacturer of the winding leads so that the user need only connect the supply and utilization lines to the transformer, and should be adapted for convenient mounting in a variety of positions and locations.

It is therefore an object of this invention to provide an improved unitary, dry-type, three phase transformer construction.

Another object of this invention is to provide a threephase, dry-type transformer construction having the desirable features set forth above.

Further objects and advantages of this invention will become apparent by reference to the following description and the accompanying drawing, and the features of novelty which characterize this invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

This invention in one aspect thereof, comprises a plurality of identical spaced-apart transformer core and coil assemblies with each of the cores having a coil with primary and secondary windings with electrical leads connected thereto. The cores are arranged in longitudinal alignment and a pair of sleeve members are respectively arranged on opposite sides of the core and coil assemblies enclosing the projecting portions of the coils Patented May 25'), 1953 ice and forming a pair of wiring compartments for making external electrical connections to the coil leads. The primary windings are located in one of the compartments and the leads of the secondary windings are located in the other of the compartments, the sleeve members having means for admitting external electrical leads thereto. The sleeve members have outwardly extending flange portions respectively formed on their side walls with mounting means for the transformer extending from at least some of these flange portions. Clamping means are provided engaging the flange portions on opposite sides of the core and coil assemblies tightly clamping the core laminations and holding the transformer in assembled relation and a pair of cover members are provided re spectively removably secured to the sleeve members and providing access to the wiring compartments.

In the drawings,

Fig. l is a view in perspective showing the improved three-phase transformer construction of this invention mounted in one position;

Fig. 2 is another view in perspective showing the improved three-phase transformer construction of this invention mounted in another position;

Fig. 3 is an exploded view in perspective showing the improved three-phase transformer construction of this invention;

Fig. 4 is a cross sectional view of the transformer of Figs. 1 through 3 inclusive showing the preferred wiring arrangement;

Fig. 5 is an end view, partly broken away, further showing the improved transformer construction of the previous figures; and

Fig. 6 is another cross sectional view of the improved transformer construction with a modified wiring arrangement.

Referring now to Figs. 1 through 5 of the drawings, the improved three-phase, dry-type transformer construction of this invention incorporates three core and coil assemblies 2, 3, and 4 respectively having cores 5, s, and 7 each formed of a stacked plurality of rectangular laminations of magnetic material with coils e, 9 and to respectively mounted thereon. Each of the coils 8, 9 and 10 includes primary and secondary windings, the primary windings having electrical leads l1 and 12 connected thereto and the secondary windings having electrical leads 13 and 14 connected thereto. The magnetic cores 5, 6, and 7 are preferably of the shell-type and preferably formed of alternated El shaped laminations with the coils 3, 9 and 10 on the center legs 22 thereof. The specific core configuration does not however form a part of this invention and is shown here as being of the E-I type for illustrative purposes only. It will be observed that the coils t5, 9 and 10 have portions 15 and 16 which project respectively beyond the opposite faces 17 and 18 of the cores 5, 6 and 7. Each of the cores 5, 6, and 7 has openings 19 and 29 extending through its laminations respectively adjacent the transverse laminated edges 21 and along the center lines of the center legs 22. The core 5, 6, and 7 are arranged in longitudinal spacedapart alignment with their laminations and their longitudinal laminated edges 23 and 24 located in the same planes and with their transverse laminated edges 21 re spectively parallel.

A pair of sleeve members 25 and 26 are provided having respectively parallel side walls 27 and 23 and end walls 29 and 30. The sleeve members 25 and 2d are respectively arranged on opposite sides of the core and coil assemblies 2, 3, 4 and the side walls 27 and 28 respectively have outwardly extending flange portions 3i and 32 formed on their longitudinal edges. The end walls 29 and 30 also respectively have inwardly extending flange portions 33 and 34.

The outwardly extending flange portions 31 and 32 of sleeve members 25 and 26 are arranged respectively abutting the opposite faces 17 and 13 of the cores 5, 6, and 7 and are respectively provided with a plurality of openings 35 which are in alignment with the openings 19 in cores 5, 6, and 7. Inwardly extending flange portions 33 and 34 of end walls 29 and 30 are likewise respectively abutting the opposite faces 17 and 18 of cores 5, 6, and 7 and have openings 36 respectively in alignment with openings 20 in the cores 5, 6, and 7. It will be observed that the outer longitudinal edges 37 of the outwardly extending flange portions 31 and 32 are respectively flush with longitudinal laminated edges 23 and 24 of cores 5, 6, and 7 while the end walls 29 and 30 are respectively flush with the outer transverse laminated edges 21 of the outer two cores and 7. it will now be observed that the leads l1 and 12 connected to the primary windings of coils 8, 9, and are all located within the sleeve member 25 which thus defines a wiring compartment 38 and the leads 13 and 14 connected to the secondary windings of coils 8, 9 and it) are located in sleeve member 26 which thus defines a second wiring compartment 39. Sleeve members 25 and 26 have a plurality of knock-outs arranged in their side and end walls 27 through 36 for providing access to the winding compartments 38 and 39 for admitting external electrical leads to the interior of the wiring compartments 38 and 39.

In order to mount the transformer assembly, angle members 41, 4-2, 43 and 44- are provided, the members 41 and 42 having their sides 67 arranged respectively abutting outwardly extending flange portions 31 and 32 of sleeve member 25' and angle members 43 and 44 likewise respectively having their sides 67 respectively abutting the outward extending flange portions 31 and 32 of sleeve member 26. The other sides of the angle members 41, 4-2, 43 and 44 are spaced from the respective side Walls 27 and 28 of sleeve members 25 and 26 and it will thus be observed that the angle members 41 through 44 inclusive with the side walls 27 and 28 define channel-shaped portions. The other sides 45 of the angle members 41 through 44 are provided with suitable openings 46 for mounting the transformer. Reference to Figs. l and 5 will show that sides 45 of angle members 41 and 43 may be arranged abutting a wall 47 and secured thereto by suitable bolts 48 extending through openings 46. 7

Angle members 41 through 44 inclusive are also provided with flange portions 49 at each end thereof, flange portions 49 also having openings 5t) formed therein. Reference to Fig. 2 will show that the transformer assembly 1 may be mounted vertically and secured to a floor or base 51 by means of suitable bolts 52 extending through flange portions 49.

In order to complete the assembly, a pair of cover members 53 and 54 are provided which are removably secured to sl eve members 25 and 26 by a plurality of studs 55 which are respectively secured to the side walls 27 and 28 of the sleeve members 25 and 26 and which extend through suitable aligned openings 56 in cover members 53 and 54. Cover members 53 and 54 as well as side walls 27 and 28 of sleeve members 25 and 26 may be provided with suitable louvers 57 for admitting ventilating air to the compartments 3% and 39.

The transformer 1 is held in assembled relation by a plurality of through-bolts 58 which extend through openings 59 in sides 67 of angle members 41 and 42, openings 35 in flange portions 31 and 32 of sleeve members 25 and 26, and openings 19 in cores 5, 6, and 7, and which clamp the laminations of the cores 5, 6, and 7 together by means of suitable nuts 66. Bolts 69 also extend through openings 36 in flange portions 33 and 34 of end walls 29 and 3t and openings 2d adjacent the outer laminated edges 21 of cores 5 and 7 and further clamp the laminations of the cores 5 and 7 by means of suitable nuts 61. The laminations of cores 5, 6, and"! are further clamped together by additional through bolts and nuts 62 and 63 extending through openings 20 adjacent the inner transverse laminated edges of cores 5, 6 and 7.

Referring now specifically to Fig. 4, it will be seen that the primary winding leads 11 and 12 may be connected together so as to connect the primary windings of the coils 8, 9 and 10 in delta-relationship with terminals 64 being adapted to connect the corners of the delta to the three lines of an external source of three phase alternating current power. Likewise, the secondary leads 13 and 14 may be connected together to connect the secondary windings of the coils 8, 9, and 10 in delta with terminals 65 likewise being adapted to connect the corners to a three phase utilization circuit.

Referring now specifically to Fig. 6, it will be seen that a pair of bracket members 68 may be secured respectively to cores 5 and 7 by means of through bolts 62 with the terminal board member 69 being secured to the other ends of the bracket members 63 by means of suitable bolts 7 0. Three groups of terminals 71 may be arranged on terminal board member 69 and connected respectively to primary windings of coils 3, 9 and 10 by leads 72, 73 and 74. The external connections to the primary windings may then be made to the terminals 71, with this arrangement being particularly suitable forprimary windings provided with a plurality of taps to accommodate different input voltages. The terminal board of Fig. 6 may also be advantageously employed on the secondary side of the transformer.

While the three phase transformer construction described above has been described in connection with three coil and core assemblies 5, 6, and 7 which may be connected in delta-Y, delta-delta, or YY, it will become apparent that this construction is equally applicable to the so called Scott-T connection in which only two core and coil assemblies are utilized.

It will now be readily seen that this invention provides a three phase dry-type transformer construction in which only two Wiring compartments are provided (one for the primary side and one for the secondary side) as compared with six wiring compartments with the previously employed three separate, single phase transformers. It will also be seen that this is a unitary transformer construction which will occupy less over-all space than the three transformers previously employed and which can be mounted and connected in much less time. By virtue of the single wiring compartment on each side, the windings can be permanently connected at the factory so that the user need only bring in the three supply lines and connect them to the three input terminals or a terminal board may be provided to permit primary winding tap changing. The construction further provides good ventilation of the coils; it will now be seen that he vertical mounting arrangement of Fig. 2 essentially provides a chimney effect. Further, universal mounting is provided in that the transformer may be equally conveniently mounted on a side wall or a floor or suspended from the ceiling. Transformers incorporating this construction have been found to be much quieter than previous constructions in which the three phase windings are arranged on a single core and it will further be observed that the laminations of the cores 5, 6, and 7 are tightly clamped together by the same through-bolts 58 which hold the entire device in assembled relation.

A 45 kva. three-phase transformer of the type shown in Figs. 1 through 5 has been constructed by the applicants assignor having a primary input voltage of 480 delta and secondary output voltage of'208Y/120. The three cores of this transformer were 9 /8 by 11% inches with a stack height of 7 inches and sleeve members 25 and 26 were 32%, inches long, 8%, inches wide, and 9 /2 inches high with flanges 32 and 33 being respectively 1% inches wide. The over all weight of this transformer was 630 pounds. 2

While I have shown and described particular embodi 'ments of this invention, further modifications and imwho. Mn"... N.

provements will occur to those skilled in the art. I de- I sire that it be understood therefore that this invention is not limited to the particular form shown and I intend in the appended claims to cover all modifications which do not depart from the spirit and scope of this invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A unitary three-phase, dry-type transformer construction comprising: a plurality of identical spacedapart transformer core and coil assemblies each having a laminated core with a coil positioned thereon, each of said coils having primary and secondary windings with electrical leads respectively connected thereto and further having portions respectively projecting beyond the opposite faces of its core, said cores being arranged in longitudinal alignment; a pair of sleeve members having side and end walls, said sleeve members being respectively arranged on opposite sides of said core and coil assemblies respectively enclosing said projecting portions of said coils forming a pair of wiring compartments for making external electrical connections to said leads, said leads of said primary windings being located in one of said compartments and said leads of said secondary windings being located in the other of said compartments. said sleeve members having means communicating with the interior thereof for admitting external electrical leads thereto, each of said side Walls having an outwardly extending flange portion formed thereon; mounting means for said transformer extending from at least some of said flange portions; clamping means respectively engaging said flange portions on opposite sides of'said core and oil assemblies clamping said core laminations and holdcover members respectively removably secured to said sleeve members closing the same and providing access to said wiring compartments.

2. A unitary three-phase, dry-type transformer construction comprising: a plurality of identical spaced apart transformer core and coil assemblies each having a laminated core with a coil positioned thereon, each of said coils having primary and secondary windings with electrical leads respectively connected thereto and further having portions respectively projecting beyond the opposite faces of its core, said cores being arran ed in longitudinal alignment; a pair of sleeve members having side and end walls, said sleeve members being respectively arranged on opposite sides of said core and coil assemblies respectively enclosing said projecting portions of said coils forming a pair of wiring compartments for making external electrical connections to said leads, said leads of said primary windings being located in one of said compartments and said leads of said secondary windings being located in the other of said compartments, said sleeve members having means communicating with the interior thereof for admitting external electrical leads thereof, each of said side walls having an outwardly extending flange portion formed thereon, said flange portions respectively abutting said opposite faces of said cores; two pairs of angle members respectively arranged on opposite sides of said core and coil assemblies, each of said angle members having one of its sides abutting one of said flange portions and its other side spaced from a respective sleeve member side wall and adapted for mounting said transformer; clamping means respectively engaging said angle members and flange portions on opposite sides of said core and coil assemblies clamping said core laminations together and holding said transformer in assembled relation; and a pair of cover members respectively removably secured to said sleeve memmg said transformer in assembled relation; and a pair of of a stacked plurality of rectangular laminations with a coil positioned thereon, each of said cores having a plurality of openings adjacent its edges extending through said laminations, each of said coils having primary and secondary windings with electrical leads respectively connected thereto and further having portions respectively projecting beyond the opposite faces of its core, said cores being in spaced-apart longitudinal alignment with their said opposite faces and longitudinal laminated edges respectivel in the same planes and with their transverse laminated edges respectively parallel; a pair of sleeve members having respectively parallel side and end walls, each of said side walls having a pair of outwardly extending flange portions formed on a longitudinal edge thereof, said sleeve members being respectively arranged on opposite sides of said core and coil assemblies and respectively enclosing said projecting portions of said coils forming a pair of wiring compartments for making external electrical connections to said leads, said side wall flange portions respectively abutting said opposite faces of said cores with their longitudinal edges being respectively substantially flush with said longitudinal laminated edges of said cores, said flange portions having a plurality of openings in alignment with some of said core openings, each of said end walls being substantially flush with a respective transverse laminated edge of an outer one of said cores and having an inwardly extending flange portion abutting a respective one of said core faces, said inwardly extending flange portions having openings formed therein in alignment with other of said core openings, said leads of said primary windings being located in one of said compartments and said leads of said secondary windings being located in the other of said compartments, said primary and secondary winding leads being connected to connect said primary and secondary windings respectively in predetermined relation, said sleeve members having means communicating with the interior thereof for admitting external electrical leads thereto; two pairs of angle members respectively arranged on opposite sides of said core and coil assemblies, each of said angle members having one of its sides abutting one of said outwardly extending flange portions and the other of its sides spaced from a respective sleeve member side wall and adapted for mounting said transformer in one group of positions, said one side of said angle members having a plurality of openings formed therein respectively in alignment with said outwardly extending flange portions openings, each of said angle members having flange portions at each end thereof adapted for mounting said transformer in another group of positions; a plurality of clamping members extending respectively through said aligned angle member, outwardly extending flange portion and core member openbers closing the same and providing access to said wiring compartments.

3. A unitary three-phase, dry-type transformer construction comprising: three identical shell-type transformer core and coil assembhes each having a core formed ings and engaging said angle members on opposite sides of said core and coil assemblies clamping said core laminations tightly togetherand holding said transformer in assembled relation; other clamping members extending respectively through said aligned inwardly extending flange portion and core member openings and engaging said inwardly extending flange portions on opposite sides of said core and coil assemblies further clamping said laminations together; and a pair of cover members respectively removably secured to said sleeve members closing the same and providing access to said wiring compartments.

4. The combination of claim 1 further having: a pair of bracket members in one of said compartments respectively secured to at least one of said cores; a terminal board member secured to bracket members; and a plurality of terminals mounted on said terminal board memher, said leads in said one compartment being respectively connected to said terminals.

No references cited. 

